I'm interested especially during peace time/stability.
Is there a limit for "power relative to liege" for them to declare war or something?
Is there a limit for "power relative to liege" for them to declare war or something?
You can't integrate a PU that's larger then you, you can annex a larger vassal just fine, you'll just get a penalty to the speed, which can easily be overcome with some dip-rep.That pic is of nationalist rebels declaring a war of independence due to rebels achieving their demands. The same thing can happen to Portugal with Ceuta creating Fezian nationalists. That's not a vassal declaring war on the overlord. That never, ever happens. There is no limit to how big your vassal can get and they will never do anything about it. You won't be able to ever integrate a vassal who has grown larger than you, though.